DePaul mentioned building a (practically) on-campus arena on the NW corner of Sheffield & Fullerton. I don't know what came of that.

As a landmark, I don't think Wrigley can be torn down.

The plan you're talking about is dead, the residents voted it down. They are looking at building their own stadium down south of the McCormick Center, or the Bulls have offered them 10 years of free rent to come play at the UC.